Variable-speed gearing for motor-cycles.



P. W. SMITH. VARIABLE SPEED GEARING FOR MOTOR CYCLES.

APPLICATION FILED JUNE 17, 1911.

2 BHEETB-SHEET 1.

Patented July 9, 1912.

3. W. SMITH. VARIABLE SPEED GBARING 011 MOTOR/CYCLES. APPLIQATIQHFILED-N71111:], 191 1,

Patented July 9, 1912.

2 SHEETS-SHEET 2.

noeaeas.

FRANK WALKER sivrirn, or nnnnicrcmnnenaivn.

ivnntnsrn-srnnn GEARING ron MOTOR-CYCLES;

To all whom it may concern:

Be it known that I, FRANK WALKER SMITH, a subject of the Kingdom ofGreat Britain, residing at the Enfield Works, Redditch, in the county ofWorcester, England, have invented certain new and useful Improvements inor Relating to Clutch Mechanism and Variable- Speed Gearing forMotor-Cycles, of which the following is a specification.

This invention comprises improvements in or relating to clutch mechanismand variable speed gearing for use on nt-otor cycles, tri-cars and othermotor vehicles, and it has for its purpose the provision of a clutch andspeed gear mechanism which is simple in construct-ion, relativelyinexpensive to manufacture, and efficient in operation.

According to the present invention, a re volving shaft is provided withdriving and driven members arranged to connect the rear wheel of themachine with the engine shaft, by means of transmission agents, two ormore of the said members being arranged at one part of the revolvingshaft and having friction clutches by which they maybe selectivelycoupled to their shaft for bringing the various gear ratios intooperation. When the clutches are free, a free engine position isprovided. Advantageously two adjacent members are arranged at or nearone end and a'single member at or near the 4 the frame. 1"

other extremity of the shaft, such members being sprocket wheels in thecase of chain transmission; by such an arrangement the driving anddriven members can be placed on opposite sides of the machine so that itis possible to use a narrower chain line than I if all the chains wereon one side. Friction clutches having internal expanding rings operatedby a common member are advantageously employed, the operating mechanismbeing arranged at that end of the} countershaft at which the clutchesare disf posed, thus enabling the revolving shaft to be a' solid one.'pBy virtue of the outside arrangement of the operating gear, a certainamount of end thrust is set up momentarily when the clutches are beingengaged or released and a cionvenientmeans of ac- 1 commodating the saidthrust takes the form of a bearing supported on an arm fixed to In orderthat this invention may be Specificationiof Letters'latent. Applicationand June 17,1911. Serial No. ea3,s11.-

clearly understood and. more readily carried into practice, referencemay be had to the appended two sheets of drawings, up'oii which:- Figure1 is a sectional plan of apparatus according to the invention. Fig. 2 isan elevation of the gear shown in Fig. 1. Fig. 3 is a sectionalelevation through one of the clutches and operating mechanism; Fig.4 isa sectional view of a detail hereinafter described. 5

In carrying the invention into effect as Patented JulyQ, 1912.

applied to a motor cycle or tri-car, the countershaft 1 is arranged at asuitable.

point on the frame and is journaled on ball bearings 2 supported by abracket 11011 7 veniently forming part of'the fraihsuch as the bottombracket 3. When the gear is to be employed with chain transmisslon, asuitably-dimensioned sprocket wheel 4:

may be secured on the one extremity 5 of the countershaft and connectedby'a chain to the rear wheel, the opposite extremity 6 of saidcounter-shaft being enlarged beyond i the supporting-:ball bearing andbored out to accommodate an axially-moving. operat- 30 ing member 7(adapted to bring the clutches into or out. of engagement with theirsprockets 8,9 which latter may be driven from the engine.

- For transmitting the drive'from the enlarged extremity of the'countershaft to the driven sprocket wheels concentric therewith,

internally expansible rings-10,- 11 are em-- ployed, said rings beinghoused in the bosses of the driven sprocket wheels. or otherwise rigidlyconnected to the enlarged extremity of the countershaft are two adjacentdisks 12 having two annuli extending sidewise in such a manner that theits periphery to accommodate the meansfor 0 expanding the rings. Totransmit the power from the expansible rings to the disk, a stud, boss,projection or the like is formed on one or theother, such as a, pin15-on the disk 12 to engage with a corresponding re- 105 cess or hole inan eye 16 on the-other .part. The means'for expanding the rings mayconvenientlyeomprise a short stud or :spin-- dle 17 passing through fromthe bore of the enlarged countershaft extremity to engage the inner partof the rings, short cylindrical split members orsleeves 18 being interfKeyed to inner annulus 13 fits on the periphery of '95 posed between thering and the stud for the purpose of insuring a gradual engagement, whenthe clutch is engaged/ The part of the expansible ring which engages theshort 5 sleeve may beof l-config1iration, the surrounding portions beingcorrespondingly shaped to suit, while'the stud 17 connecting the slidingmember 'withthe short sleeve 18 may be reduced in diameter at its outerpart 19 and suitably rounded oif'at its inner part 20. The sleeves maybe eccentric in cross section to increase their resiliency, with theslit at the thinnest part.

To efiect radial displacement of thestuds.

5 necessary to expand the clutch rings, a body 7 conveniently -offaceted or cylindrical form is arranged in the hollow end of thecountershaft concentrically with the driven sprocket wheels and isprovided with a. plu- 20 rality such as three of longitudinal grooves 21see Fig: 4, depressions, or facets 2l 'see Fig. 3 of a cam-likeconfiguration so ar-. ranged in relati'on to the two studs that in themiddle'position'both studs are in'the in- Ward position as shown in Fig.1, whilewhen the cambody is moved outwardly, the

top studis operated and the correspondingclutch ring expanded or viceversa, thus giv ing a free engine in conjunction with the two speeds. Byforming the facets or grooves of different depths, wear is very readilytaktii up as it is only necessary to annulus in order to accommodate ashort non-rotatable operating spindle 22 which spindle'is moved inwardin the preferred manner; bymeans of a rack 23 and pinion 24 the rackteeth being formed in the outer extremity of'the said spindle 22, whileits inner pqrtion25 projects into the enlarged countershaft end 6 toengage with the cam and for this purpose is furnished with suitable'anti-friction'or thrust bearings 26. A

housing 27 journally supports the vertical shaft 28 on which the toothedpinion 24 is carried and conveniently the said housing may also supportthe non-rotatable spindle 22 at that part at whichthe teeth are formed.-In lieuof the rack and pinion any other suitable meansmay be employedfor op'crating the cam'body.

To prevent as far. as possible any strain on the countershaft fromtaking place when the clutch is being operated, an outerbearing mayincorporated and may conven- 66 ie ntly take the form-of a double thrustloall or groove which being shallower than thebearing'29, an annulardisk 30 being screwed onto the enlarged extremity of the countershaftwhile annular .ball races 31 one on 'each side of the saidcone areconveniently pinion, the outer ball race being positioned v in the innerface'of the boss 33 or enlarged part of the arm, while the inner ballrace is secured to the said arm by screws 34: and encircles the cone,the whole being so com-. bined as to inclose' the entire operatingmechanism and thereby preclude the exudation of oil or ingress of dust,The said stiffening arm effectually supports the coun-' tershaft andenables it. 'to satisfactorily transmit power to the back wheel,asuitable 5 anchorage for the rigid"extremity of the arm being formed bya bracket or lug 35 with extending arm 36 brazed or otherwise secured toa partof the frame close to the bottom bracket. For facilitatingadjustment of the arm in the process of manufacture, the rigid extremitymay be coupled to thebracket arm 36 by an eccentric connectioncomprising a sleeve'37 pin 38 and looking nut 39 which allows the.distance between the centers of the arm 36 and the clutches to beadjusted to a high degree of accuracy to. suit the particular machine towhich it is applied.

The vertical shaft 28 aforementioned for rotating the toothed pinion'inthe process of operating the gear may be connected by a universal jointto the shaft leading to the opntrol shaft so that the control lever mayI he placed in a plane diflerent from that 00- cupied by the toothedpinion and yet transmit' movement satisfactorily thereto. A- convenientform of universal joint consists in .forming in the said vertical shaft28 a hole or recess 4010f square orother appropriate shape with which amember ilsquare in section, on the b'ottomof thecontrol rod, is adaptedto engage. .To allow however of the required universal movement,theengaging faces of the square section member are not flat planes asare those of the hole but-are of a convex or partly spherical contour sothat while effecting the transmission of movement in a satisfactorymanner, the universal action is in no way impeded.

' Conveniently the ball bearings of the countershaft' are carried in asleeve 42 which sleeve has a head 43' at one extremity and is adapted'to receive a nut 44 at the other, thereby allowing the entire gear tobe passed into the bracket provided for its reception, as .aself-contained unit, the screwing up of the nut being all that isnecessary to then retain the gear in position. Bysuitablyincreasingsprocket-being in the one case coupled to the number of transmissionagents and clutches it, will be readily understood that three, or morespeeds could be accommodated while it will be obvious that a belttransmission could if desired be readily "adopted in place of or inconjunction with chain. 'It

the back .wheel while in the other it isconneot'edfto the motor. In 2the' embodiment shown, the adjacent members are, of equal diameter" anddifferent sized wheels are emcombination with a frame, of a shaftmounted ploy'ed'on the'engine shaft or on the rear wheel hub as the casemay be but it will be obvious that the adjacent members could be of:different diameters in which'case the corresponding en ine'i or road,wheelmembers would be sui'ta 1y dimensioned to correspond withtherequired gear-ratios.

' What I-clalm as'my invention and desire" I to secure by Letters Patentis 1. In a clutch; and variablespeed caring for motorcyclesc'or likemotor vehic es, the

combination: with a frame; of a solid shaft mounted therein and having ahollow portion,-rin or wheel" bearing members fixed to said she t,adjacent wheels rotatable on 'said members, friction elements for,frictionally couplin said wheels with. said members, a longitu inallyand axiall movable cam in said hollow portion, an devices actuated uponmovement of said cam for operating said elements to frictionaliy coupleeither of said wheels with said bearing members,

I substantiall as described,

2: In a c nteh and variable speed gearing for motorcycl s .or like motorvehicles, the

' combination with-a framaofa shaft mounted therein and havin a hollowportion, adjacent-wheels rotata le about said shaft near one end, adriven wheel on said shaft at the other 'end thereof, friction elementsconnec'ted with said shaft for frictionally coupling said adjacentwheels thereto, a longitudinally movable cam in said hollow portion, anddevices actuated upon movement of said cam for operatingsaid frictionelement to couple either of said wheels with said shaft, substantiallyas described.

3. In a'clutch and variable speed gearing form'otorcycles or like motorvehicles, the comblnationwith a frame, ofa shaft mount- ,ed therein andhaving'a hollow portion,

wheel bearing members fixed to said shaft, ad acent wheels rotatable onsaid members, friction elements connected with said memhere forfrictionally coupling said wheels therewith,- devices. for actuatingsaid eleinents to throw said wheels into coupling re- 4. In a clutch andvariable speed caring for motorcycles or like motor vehic es, the

therein and havin a hollow portion, wheel bearing members rotatable onsaid members, friction elements fixed to said shaft, wheels connectedwith said members for fricti-onally coupling said wheels thereto, alongi tudinally movable'cam in said hollow por tion, and devices adaptedfor engagement with said cam and having yielding portions engaging saidfriction elements for actuating the same, substantially as described.

5. A clutch and variable speed gearing'for motorcycles or like motorvehicles, the combination with a frame, of a shaft mounted therein,adjacent wheels rotatable about said shaft, friction elements connectedwith said shaft' for coupling" either of said wheels therewith, studshaving yielding elements for engaging said friction elements to expandthe same, and a cam for actuating said studs, substantially asdescribed.

6. In a clutch and variable speed gearing for motorcycles or like motorvehicles, a frame, a sha ft mounted therein, wheel hearing membersconnected with said shaft and having split rigid rings, a wheel looselydis posed on each member, expansible split fric tion elements embracingsaid rings, and means extending through the divided portions of saidrings for expanding said ele ments, substantially as described.

In witness whereof I have hereunto set my hand in the presence of twowitnesses this 15th May 1911.' FRANK WALKER SMITH.

Witnesses:

T. O. PALIHELT, T. E. Lam

